In the general area of lithography, the transfer of an image to an associated substrate (medium) can be carried out by creating an XY pattern (2-dimensional array) of the desired image whereby X is the number of image elements along one axis and Y is the number of image elements along a second axis. The XY image is then used to expose the substrate in such a way as to write or otherwise transfer the image to the substrate.
In the case of high resolution lithography such as used in the manufacture of semiconductors, the size of each image element can be measured in very small units, such as nanometers, nm (10−9 m). For example, an overall image with an X dimension of 50 micrometers, nm (10−6) and a Y dimension of 50 um which contains 1000 image elements in the X dimension and 2000 image elements in the Y dimension will have an image element size of X=50/1000=50 nm and Y=50/2000=25 nm. That is, each element, or pixel, in the image would be 50×25 nm in size.
This XY image can be applied to a substrate using an XY stepper mechanism whereby the substrate is stepped in the X dimension to expose one line of the substrate at a time. In the above example, this would require 1000 steps of 50 nm each step for a total X distance of 50 um. The substrate would then be stepped in the Y dimension and the next line of the XY image would be exposed. Alternatively, instead of stepping the substrate, the substrate could be maintained in a stationary position and the exposure beam could be stepped in the XY dimensions.
While operable, there are a number of limitations with the foregoing approach. One limitation relates to the excessive memory requirements to store relatively large, high definition images. For example, a 100 mm×100 mm image which has a resolution of 5 nm in both dimensions will contain 100,000,000/5=20,000,000 image elements in both dimensions. This results in a total file size of about 400 terabits, or 50 terabytes of information. Storage and accessing of such a large file can be problematic. Another limitation with the transfer of images as set forth above is the relative expense and complexity of substrate/beam stepper systems for the required resolution and range to accommodate such relatively large images.